Blackleg in cattle has been recognized since 1938 in Iran that mostly affects cattle in enzootic farm. Main object of this study was to prepare and formulate a concentrated potent vaccine for immunization of cattle against blackleg in Iran. Experimental concentrated blackleg vaccine was prepared according to the method described by FAO. The medium (Modified medium for production of experimental C. chauvoei vaccine by fermenter) consisting of peptone, glucose, sodium chloride, cysteine hydrochloride and yeast extract was prepared by fermenter and inoculated by Clostridium chauvoei strain for preparation of blackleg vaccine. Aluminum hydroxide gel adjuvant was added to the high yield vaccine. The vaccine was also concentrated by the method of precipitation. None of tested animals showed any local or general adverse reactions. All of vaccinated guinea pigs resisted the challenge with 4 MLD of virulent C. chauvoei.